Concern about adverse health effects caused by potentially dangerous ambient electromagnetic radiation continues to grow. Such concern persists partially because recent scientific studies indicate a link between exposure to ambient electromagnetic fields and cancerous disease. For instance, prolonged exposure to electromagnetic radiation from electric power lines may cause leukemia. These studies however lack a strong nexus between data indicating the extent of exposure to an electromagnetic field and the corresponding health conditions of the exposed person for example. Accordingly, a device which is more suitable to measure and record exposure to ambient energy fields and activities therein over an extended period of time is needed to improve the accuracy of these studies.
Related art includes U.S. Pat. No. 4,659,984 to Doss, which discloses a passive, integrating electromagnetic radiation power dosimeter. The dosimeter includes an antenna for receiving and interacting with incident electromagnetic radiation, a diode for rectifying the alternating voltage generated by the antenna, a network for generating a current proportional to the square of the direct current voltage produced in the rectification process, an electrochemical storage cell for producing an integrated response, and a voltage measuring device for measuring the integrated response. The dosimeter as disclosed in the Doss patent has several shortcomings. First, the receiving antenna of Doss does not distinguish the electromagnetic radiation it receives into three different axes or into different frequency ranges. Doss also does not convert the detected electromagnetic radiation into a form of data which can be easily read and analyzed by a computer in terms of exposure at regular intervals. Instead, a cumulative dose type of data is provided according to the Doss patent. Further, Doss does not measure or store the activity of a person handling or wearing the dosimeter.
Other related art includes U.S. Pat. No. 5,134,370 to Jefferts et al. The Jefferts et al. patent discloses an apparatus for detecting a magnetic tag implanted in an organism. The apparatus has a group of magnetic field detecting coils which have outputs balanced against one another in an uniform magnetic field. Such coils are moved past a stationary specimen to detect a different magnetic field, and the apparatus then generates a signal in response to the presence of an additional magnetic field. The apparatus disclosed in the Jefferts et al. patent is basically a metal detector which concentrates more on simple detection of a change in the magnetic field rather than measuring and storing data of electromagnetic radiation over an extended period.
Related art also includes U.S. Pat. No. 5,151,649 to Heroux, which discloses a portable instrument for measuring current in straight conductors. The instrument comprises a pair of triaxially-oriented magnetic flux density sensors. The instrument also comprises a multiplexer-ADC electronic circuit, a microprocessor, and a display unit. The Heroux patent focuses on accurate measurement and display of the electric current within the conductor, and shields the magnetic flux density sensors against the electric field of the conductor. The instrument does not store the information with respect to time.